U.S. Pat. No. 4,427,663 to Mrozik describes the use of certain 4"-deoxy-4"-amino derivatives of avermectin compounds, including N-alkyl derivatives. The compounds are described as being anthelmintics and agricultural insecticides. It has been surprisingly discovered that 4"-deoxy-4"-N-methylamino avermectin Bla/Blb has a significantly higher level of activity and lower level of mammalian and aquatic life toxicity when compared to other 4"-amino compounds and other related avermectin compounds.